Investigation On The Corrosion Measuring Methods For Three Kinds Of Contact Materials In SO₂ And HNO₃ Vapor

Electric connectors play an important role in our daily life. The reliability of the small contact points affects the operation of the electric and communication systems. The properties of electric contact material are of great importance for the contact point reliability. As the society develops quickly, we pay more attention on the atmospheric environment. But it's very common that there're some accidents on account of the failure of the contact materials. Some corrosive gases such as SO₂ and NO₂ will do harm to the exposed connectors. So the investigations on the corrosion measuring methods for three kinds of contact materials in SO₂ and HNO3 vapor are of great significance.The main content of this paper is to study the corrosion test methods for Au-Ni-Cu,Ni-Cu and Cu samples in SO₂ and HNO₃ vapor, including the comparison and analysis for several kinds of corrosion standards, the appearance and components of the corrosion products and the optimization for more factors.Porosity is an important factor to evaluate the quality of gold plating. We will do corrosion research on the gold plating samples according to the ISO 6988-1994(SO₂),JIS-H-8620,ASTM B799-2005 and ISO 14647-2000(HNO₃ Vapor) standards in which some of the parameters are optimized. The experiments shows that the SO₂ corrosion test based on JIS standard has the best maneuverability, but needs a long test period. HNO3 Vapor standards can have good test performance in short period.We also have study on the Ni-Cu and Cu samples according the ISO 6988-1994 standard with different temperatures and HNO₃ Vapor standards with different times. The components of the SO₂ corrosion test were sulfates for nickel and cupreous. The components of the HNO₃ Vapor test were the nitrates and oxides for nickel and cupreous.As the temperature and the time have different effect on the corrosion test, we will make use of the orthogonal test to distinguish the primary and secondary when there're several factors. It is presented that the influences of the parameters such as duration, temperature, concentration and plating thickness in porosity test by Nitric acid vapor is applied. The orthogonal test method was adopted to reduce the test times and make the data analysis easier.